What does the refresh window option "Flush cached joined results" mean. What would I need this for?

I have not been able to find any information on it in the Help section of Filemaker.

FM 7.0v3

This is new in FMP 7.0v3.

I think that it means that FMP will refresh all found sets in all other windows related to the table occurrance associated with the layout, and not just refresh the current window.

Something like that.

I thought it meant it would refresh data displayed in a portal ?

Yes, it means that portals will update...

This is particularily useful for portals that are based on complex calculations that are in part based on other relationships that are not visible on the layout.

For example, when the leftside of the relationship for a portal is a calculated field that makes use of that valueListItems calculation (which of course makes use of a relationship). If you modify data in a script that would change the valuelistItems, in v7.02 the valuelistitems would be updated but not the cached calculation using it. hence, the portal based on this calculation would not be updated (even it the calcuation was unstored) In V7.03 by adding this option, all relationships and calculations would be uncached and updated. Hence the portal based on this calcuation would reflect the change made by the script.